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RE: pteros have lift-off

> From: owner-DINOSAUR@usc.edu [mailto:owner-DINOSAUR@usc.edu] 
> On Behalf Of Tim Williams>
> > And getting back to that arboreal theory, which theropods prior to 
> > Archaeopteryx and kin had long forelimbs?
> One of the diagnostic characters of Coelurosauria is: 
> "Elongate forelimb exceeds half the length of hindlimb and/or 
> presacral vertebral column" (e.g., Gauthier, 1986).  This is 
> apparent in forms such as _Coelurus_ and _Tanycolagreus_ 
> (both possibly basal tyrannosaurs), _ornithomimosaurs, 
> therizinosaurs, oviraptorosaurs, and deinonychosaurs.  These 
> taxa, while found in strata not older than _Archaeopteryx_, 
> lie outside the clade that includes "_Archaeopteryx_ and kin" 
> (by which I interpret to mean Avialae).

_Guanlong_, a basal tyrannosauroid, is older than _Archaeopteryx_.
Additionally, many of the dinosaur-bearing strata in the Morrison are of
Kimmeridgian age, making them older (although not by much) than the
Tithonian _Archaeopteryx_.

Thomas R. Holtz, Jr.
Email: tholtz@umd.edu   Phone: 301-405-4084
Office: Centreville 1216                        
Senior Lecturer, Vertebrate Paleontology
Dept. of Geology, University of Maryland
Fax: 301-314-9661               

Faculty Director, Earth, Life & Time Program, College Park Scholars
Fax: 301-405-0796

Mailing Address:        Thomas R. Holtz, Jr.
                        Department of Geology
                        Building 237, Room 1117
                        University of Maryland
                        College Park, MD 20742 USA